'use strict'

signal = require 'src/signal'

module.exports = (impl) ->
    {Item} = impl.Types
    {round} = Math

    cache = Object.create null

    createImage = (src) ->
        img = document.createElement 'img'
        img.src = src

        img.addEventListener 'error', ->
            obj.status = 'error'
            obj.onLoaded.emit()

        img.addEventListener 'load', ->
            obj.status = 'ready'
            obj.width = @naturalWidth or @width
            obj.height = @naturalHeight or @height

            if obj.width is 0 and obj.height is 0 and ///\.svg$///.test(obj.source)
                xhr = new XMLHttpRequest
                xhr.overrideMimeType 'text/xml'
                xhr.open 'get', obj.source, true
                xhr.onload = ->
                    {responseXML} = xhr
                    svg = responseXML.querySelector 'svg'

                    viewBox = svg.getAttribute 'viewBox'
                    if viewBox
                        viewBox = viewBox.split ' '
                    else
                        viewBox = [0, 0, 0, 0]

                    obj.width = parseFloat(svg.getAttribute('width')) or parseFloat(viewBox[2])
                    obj.height = parseFloat(svg.getAttribute('height')) or parseFloat(viewBox[3])

                    obj.onLoaded.emit()
                xhr.onerror = ->
                    obj.status = 'error'
                    obj.onLoaded.emit()
                xhr.send()
            else
                obj.onLoaded.emit()

        obj =
            source: src
            status: 'loading'
            width: 0
            height: 0
            elem: img
        signal.create obj, 'onLoaded'
        obj

    getImage = (src) ->
        if r = cache[src]
            return r
        r = createImage src
        unless /^data:/.test(src)
            cache[src] = r
        r

    onImageLoaded = ->
        data = @_impl
        img = data.image

        if img.source is data.source
            callCallback.call @
        return

    callCallback = ->
        data = @_impl
        img = data.image
        {callback} = data

        data.innerElem?.style.display = if img.status is 'ready' then 'block' else 'none'

        if img.status is 'ready'
            callback?.call @, null, img
        else if img.status is 'error'
            callback?.call @, true
        else
            img.onLoaded onImageLoaded, @
        return

    DATA =
        innerElem: null
        callback: null
        source: ''
        image: null

    DATA: DATA

    createData: impl.utils.createDataCloner 'Item', DATA

    _getImage: getImage
    _callCallback: callCallback

    create: (data) ->
        self = @
        Item.create.call @, data

        innerElem = data.innerElem = document.createElement 'img'
        innerElem.style.display = 'none'
        data.elem.appendChild innerElem
        return

    setImageSource: (val, callback) ->
        val = impl.utils.encodeImageSrc val

        data = @_impl
        data.innerElem.src = val
        data.source = val
        data.callback = callback
        data.image = getImage val

        callCallback.call @
        return